A general loudspeaker includes a vibration system having a diaphragm, a voice coil, and a frame, and a field portion having a yoke, a magnet, and a plate.
When such a loudspeaker is mounted in a cabinet for formation of a speaker device, the frame is generally fixed to an outer shell of the cabinet at a periphery of a sound emitting side of the loudspeaker.
There are many cases where the loudspeaker has its center of gravity located in the field portion because the field portion of the loudspeaker has the yoke and the magnet that weigh more than the diaphragm does.
As such, weight of the loudspeaker mounted in the cabinet is not well-balanced in the general speaker device, and when the loudspeaker is driven, there are cases where vibration of the diaphragm is transmitted to the cabinet through the frame, thus causing distortion in sound reproduced by the loudspeaker.
PTL 1 discloses a speaker device. In this speaker device, a field portion is disposed inwardly of a frame for adjustment of weight balance of a loudspeaker (namely, a position of a center of gravity of the loudspeaker), and a plane at which the loudspeaker is mounted is aligned with the center of gravity of the loudspeaker.